A polymer formed article such as a plastic film is inexpensive and exhibits excellent workability. Therefore, such a polymer formed article is provided with a desired function, and used in various fields.
For example, a gas barrier plastic film that prevents permeation of water vapor and oxygen is used as a food/drug packaging film in order to suppress oxidation and denaturation of proteins, oils and fats, and the like to keep the taste and freshness.
In recent years, use of a transparent plastic film as a substrate instead of a glass plate has been proposed for displays (e.g., liquid crystal display and electroluminescence (EL) display) in order to implement a reduction in thickness, a reduction in weight, an increase in flexibility, and the like. However, since a plastic film tends to allow water vapor, oxygen, and the like to pass through as compared with a glass plate, the elements inside of the display may deteriorate.
In order to solve this problem, Patent Document 1 discloses a flexible display substrate in which a transparent gas barrier layer formed of a metal oxide is stacked on a transparent plastic film.
However, since the transparent gas barrier layer formed of a metal oxide is stacked on the surface of the transparent plastic film by vapor deposition, ion plating, sputtering, or the like, cracks may occur in the gas barrier layer when the substrate is rounded or folded, so that the gas barrier capability may deteriorate. The gas barrier film disclosed in Patent Document 1 also has a problem in that a pinhole is easily formed in an additional layer formed on the gas barrier layer due to insufficient surface flatness. Therefore, the gas barrier film cannot be reliably used for an electronic device member.
Patent Document 2 discloses a gas barrier laminate that includes a plastic film, and a resin layer that contains a polyorganosilsesquioxane as the main component and is stacked on at least one side of the plastic film.
However, since it is necessary to further stack an inorganic compound layer in order to obtain a gas (e.g., oxygen and water vapor) barrier capability, the process becomes complicated, and the production cost increases. Moreover, toxic gas may be used.